\tikzset{
  /Flow diagram/.style={
      % Node placement
      auto,
      node distance=14mm and 14mm,
      on grid,
      % Edge style
      thick,
      ->,
      >=Stealthy[round],
      % Node border styles
      rectangle/.style={shape=rectangle, draw, rounded corners, minimum size=8mm},
      state/.style={shape=circle, draw, inner sep=0pt, minimum size=6.8mm},
      no_border/.style={shape=rectangle, inner sep=1pt},
      % Node fill styles
      unobserved/.style={},
      intervention/.style={dcolorb, very thick, fill=dcolorb!30},
      observation/.style={dcoloro, very thick, fill=dcoloro!30},
      %
      annotation_brace/.style={-,decoration={brace,amplitude=7pt},decorate,thick,color=ann_col},
      %
      roundline/.style={rounded corners=4mm}
    },
}
